2359glenn | studio

[whirlwind]

 

Oh I have not tried the 6080 yet. Tonight will be the night and I will post impressions thereafter

What i meant is - there is a switch at the back for switching between 5998 & 6080. The WE421A & 6336 are meant to be run with the switch on 5998 setting.

This switch gives the 5998 a heck of a lot of authority, love these tubes in my amp.
 
I am going to try two per channel, just for the fun of it...even though I know that it will be overkill.

 

[2359glenn]

 

 

Oh I have not tried the 6080 yet. Tonight will be the night and I will post impressions thereafter

What i meant is - there is a switch at the back for switching between 5998 & 6080. The WE421A & 6336 are meant to be run with the switch on 5998 setting.

This switch gives the 5998 a heck of a lot of authority, love these tubes in my amp.
 
I am going to try two per channel, just for the fun of it...even though I know that it will be overkill.

You never can tell four 5998s might sound great!  Never tried it I only have two 5998s

 

[Rossliew]

You never can tell four 5998s might sound great!  Never tried it I only have two 5998s

I recall reading that the amp can even take 2 6as7 per channel. Is this true?

 

[gibosi]

Yes, in your Glenn OTL, you can run four, or two per-channel, of each of the following: 6080, 6AS7, 5998, WE421A, 7236, 6H13, 6N5P or 6520.

 

[leftside]

  The WE421A is an Uber 5998. You are running the WE421A with the 5998 / 6080 switch on 5998, right ?

Some WE421A's are rebranded 5998's. Some are "Uber". I posted my findings and pics in this thread:
http://www.head-fi.org/t/506133/visual-evidence-tung-sol-5998-western-electric-421/15

 

[Rossliew]

  Yes, in your Glenn OTL, you can run four, or two per-channel, of each of the following: 6080, 6AS7, 5998, WE421A, 7236, 6H13, 6N5P or 6520.

Would one be able to mix and match e.g. two 6080 on one channel and another two WE421A on the other?

 

[Rossliew]

On a separate note, i am now listening to the following tube combo :
 
USAF 596 (w/ adapter)/WE421A/Sylvania Chrome Dome 6SN7
 
I'm getting back some familiar body to the music - tonally it is more fleshy and fuller bodied with more audible bass but not bloated. Almost Stax-like in bass through my PM-2s i.e. bass can be heard but not felt like a punch in the gut. Curiously everything sounds balanced although it is not heart-thumpingly so. Pardon my lack of expressive words to describe the listening experience. More mids-centric but not in the romantic midrange sound of an LCD2 for example.

 

[gibosi]

  Would one be able to mix and match e.g. two 6080 on one channel and another two WE421A on the other?

 
You can... but why would you? Normally, we want to treat both channels as equal as possible. To use a pair of 6080 on one side and a pair of 421A on the other would be like using two different amplifiers, one for each channel. Seems way too strange to me......
 
But installing one 6080 and one 421A in each channel, would be perfectly acceptable.

 

[Rossliew]

   
You can... but why would you? Normally, we want to treat both channels as equal as possible. To use a pair of 6080 on one side and a pair of 421A on the other would be like using two different amplifiers, one for each channel. Seems way too strange to me......
 
But installing one 6080 and one 421A in each channel, would be perfectly acceptable.

Hahahaha...just a thought! Nonetheless, good to learn about this flexibility but i suppose one may get channel imbalances of some sort due to the different output ratings of the respective tubes.

 

[Xcalibur255]

  Some WE421A's are rebranded 5998's. Some are "Uber". I posted my findings and pics in this thread:
http://www.head-fi.org/t/506133/visual-evidence-tung-sol-5998-western-electric-421/15

This is an interesting discovery if true.  It's been widely believed that all 421A tubes were made by Tung-Sol, the minor differences attributable to what was likely a tighter tolerance specification imposed by WE.  The 5998s themselves varied quite a bit in terms of small construction details which also made it hard to nail down.
 
You're probably going to send the price of these tubes skyrocketing on eBay. 

 

[TonyNewman]

My baby is back and working perfectly. Local repair fellow has done a fantastic job.
 
Unfortunately the only 300Bs I have on hand right now are EATs. These are excellent quality tubes (similar to EML flat plate) but they are very neutral and "solid state" sounding. Combined with the ultra-transparent PY500 and C3Gs you get a result that doesn't have much tube magic happening. Extremely detailed and extended - but the tonality isn't what you would expect from a tube amp. A solid state sound from a highly capable tube amp. I originally got the EATs to calm down my WA5 - sometimes it could get a little too euphonic and "tubey".
 
A set of TA300Bs are on order. Until they show up I will have to "slum it" with the EATs - some amp porn:
 

 
Running the bias at 60mA for now. SQ is excellent.
 
EDIT - after an hour or so running the EATs the tubes have settled down a little and the tonality is not so bad. Still missing that Takatsuki magic, but these are very nice 300Bs. Detail and treble extension are excellent, bass is not quite as powerful and tight as the Taks but is still very good. There is some limited mid range tube goodness but the Taks reign supreme here.
 
These EATs had plenty of hours on them, but had been sitting idle for about 6 months prior to the repair. Not surprising that they might a few hours to "wake up".
 
For emotional engagement the V281 is still the winner, but I think a more appropriate 300B will change that.

 

[gibosi]

I am very skeptical about the claim that WE421A were being manufactured as late as 1985. Halo getters began to appear around 1960. And therefore, based on the getter shape alone, that tube could have been manufactured as early as the mid-1960's. I would like to see what markings and/or other construction details folks are using to conclude that it was manufactured in 1985....
 
Switching to music, which I assume is the reason most of us have a Glenn amp, is anyone else listening to Sam Beam and Jesca Hoop's new album, "Love Letter for Fire"? In my opinion, this is really good stuff.
 
https://www.youtube.com/watch?v=MAzgRAs-qAs
 
And I am still really digging the Sylvania 6BX7/GEC U18/20 combo, and have begun to roll through my collection of E80CC/6085. I have four manufactured by Philips, one each from Eindhoven, Hamburg, Heerlen and New York, and one manufactured by Tungsram. For those not familiar with this tube, it has significantly lower distortion and better linearity than the C3g and is considered by some as a premium version of the 12AU7. It is a wonderful tube used as a driver in an OTL, but unfortunately, it isn't powerful enough to drive a 300B. These have the same pinout as a 12AU7, and can therefore be run in 12-volt circuits (using a 6DJ8/6SN7 adapter) or 6-volt circuits (using a 12AU7/6SN7 adapter).
 
 
Tungsram (1961) on the left and Philips/Eindhoven (1955) on the right 
 

 

[leftside]

  I am very skeptical about the claim that WE421A were being manufactured as late as 1985. Halo getters began to appear around 1960. And therefore, based on the getter shape alone, that tube could have been manufactured as early as the mid-1960's. I would like to see what markings and/or other construction details folks are using to conclude that it was manufactured in 1985....
 

I am also not convinced. This is what I was told by Brent Jesse:
"The 8526 indicates most likely the 26th week of 1985. The 813 may be 13th week of 1958"
 
I'm going to ask a few more tube sellers I know. I'll update the other thread if I find out anything. All I know for sure is that I have a TS 5998 and a WE421A that look exactly the same, and a WE421A that looks completely different.

 

[gibosi]

  I am also not convinced. This is what I was told by Brent Jesse:
"The 8526 indicates most likely the 26th week of 1985. The 813 may be 13th week of 1958"
 
I'm going to ask a few more tube sellers I know. I'll update the other thread if I find out anything. All I know for sure is that I have a TS 5998 and a WE421A that look exactly the same, and a WE421A that looks completely different.

 
I would agree that "8526" sure seems to indicate 1985. Interesting... I would never have guessed that this tube was still being manufactured at that time. But Cetron did purchase some part of Tung-Sol in the 1970's. And it is my understanding that power regulator tubes were among the last vacuum tubes to be replaced by suitable solid state devices. So it would seem that Cetron kept this part of the business going as long as there was adequate demand.
 
Regarding the two different WE421As....  In my experience, for reasons we can only guess, incorrectly labeled tubes are not all that uncommon. For example, we occasionally see the wrong tube number, the wrong brand and even the wrong country of origin. And thus, my rule is the label should never to be trusted. It is always necessary to closely examine the construction to determine if the label is accurate.
 
I continue to believe that all WE421A have bottom getters. And thus, in my opinion, if the tube has top getters, it is a 5998, and not a WE421A. That said, not all 5998 have top getters. Once in awhile we see a 5998 with bottom getters. My conjecture is that these 5998 with bottom getters are simply WE421A that did not test up to spec when measured in the factory. Even though they failed to meet WE421A specifications, they still met or exceeded 5998 specifications, and rather than throw them away, they were distributed and sold as 5998.
 
So it appears that you have a 5998 that was labeled incorrectly as a WE421A. The construction - top getters, and your own listening tests would seem to substantiate this conclusion.
 
My advice, when looking to purchase WE421A, if there are top getters, let someone else buy them. And I suggest that it might also be worthwhile to keep an eye out for 5998 with bottom getters. If my conjecture is correct, even though these tubes didn't test good enough to be labeled as WE421A, they just might still sound like WE421A.
 
But again, this is just my attempt to make sense of what we see.... and I could well be wrong....
 
Cheers

 

[SonicTrance]

^^
Well said gibosi!
 
I've actually seen quite a few WE421A's on ebay with date codes suggesting 198X. No 5998's with 1980's codes though. Not sure what to make of that.
 
Edit: Here's an example:
http://www.ebay.com/itm/LOT-2-Western-Electric-421A-matched-pair-NOS-with-original-box-6AS7-5998-6080-/182023348072?hash=item2a616fdf68%3Ag%3A~HYAAOSwe7BWv~xc&nma=true&si=G4WS8G%252BCg4ABqHYlKb8eb%252F9S3L8%253D&orig_cvip=true&rt=nc&_trksid=p2047675.l2557
 
They used a different font for the yellow branding on the newer tubes.